Sunday, August 18, 2013

Our Clean Energy Future

This article was originally posted at Peak Energy - Our Clean Energy Future.

The original article will remain a snapshot but the version here will evolve over time, with snapshots being posted periodically at Peak Energy..

Following on my recent post bidding Farewell to The Oil Drum, I'd like to have a look at what I view as our longer term future for energy production and consumption.

As noted in my previous post, for the time being the combination of unconventional oil extraction and the ramping up of extraction of natural gas (from both conventional and unconventional sources) has continued to push the point of peak oil production out into the future, defying the predictions of the more pessimistic peak oil observers. During this period we have seen a boom in the research and development of solutions to help us eliminate our dependency on fossil fuels, which I'll explore in this post.

Solutions can be divided into 3 groups :

  • Renewable energy - solar power, wind power, geothermal power, hydro power, ocean energy and biomass derived power (including biofuels)
  • Distribution of renewable energy - energy storage and the electricity grid
  • Adopting alternatives to oil and other fossil fuels - electric transport, bioplastic, alternatives to fossil fuel based fertiliser and new models for manufacturing, construction and agriculture

Renewable Energy

The graphic below shows the energy available from renewable energy sources annually compared to global energy consumption. The numbers are intended to give a rough idea of relative scale - for any given energy source a wide range of estimates can be found in the literature so the numbers are indicative.

These numbers in some ways understate the amount of energy potentially available (ignoring solar power potential at sea or in space, for example, or wind power at high altitudes or far offshore, or geothermal power deep below the surface of the earth) but still serve the demonstrate that the renewable energy available to us is orders of magnitude larger than our current global energy consumption.

The contribution made by renewable energy to our energy needs is expected to exceed that made by gas (and double that made by nuclear power) by 2016, though progress needs to be accelerated if we wish to create a sustainable energy system.

Solar power

Solar power is the largest energy source available to us, dwarfing all other sources - renewable and non-renewable. Approximately 36,000 Terawatts of power could be captured by land based solar power generation - compared to current global energy use of around 16 TW. As a result, most of the plans floated for shifting to 100% renewable energy (examples include proposals by Mark Jacobson and Stuart Staniford and local plans for countries like Germany and Australia) rely primarily on solar power.

Solar power is not only the largest energy source available to us but it is also the fastest growing energy source, with solar power generation increasing by over 58% in 2012.

There are a number of options for harnessing solar power - power generation using solar photovoltaic (PV) cells and solar thermal arrays along with passive solar techniques such as solar hot water heaters.

I have been of the view that solar thermal power generation (also known as concentrating solar power or CSP) would become our most important source of power in the longer term. This view was based on a number of advantages that solar thermal possesses - it does not require rare or expensive materials (enabling it to scale without hitting resource limits), it can be built on (and is best suited to) arid land that has few other uses, it can incorporate energy storage (thus avoiding the intermittency issue), it is compatible with the existing centralised generation model and it can be combined with traditional sources of power generation (coal or gas) in hybrid power plants that allow an easy transition using existing connections to the electricity grid.

An area of desert around 250 km by 250 km covered with solar thermal power generation could supply all the world's current electricity demand.

To my continuing dismay, this hasn't happened yet (though it was our fastest growing energy source in 2012) - primarily due to the lack of progress in pushing down costs - the LCOE (levelised cost of energy) of solar thermal still being around twice that other renewable energy options.

I retain some hope given that solar thermal technology remains relatively immature - there was a very long gap between the original plant (SEGS) built in California in the 1980s and the next generation of plants built in Spain beginning in 2007 and the south west of the US shortly afterwards.

Construction of plants is now spreading around the globe, with plants being built in Abu Dhabi, Kuwait, Saudi Arabia, Egypt, Israel, Morocco, Algeria (though at this point the immense Desertec proposal has fallen off the radar), South Africa, India, China and Chile.

While there are encouraging signs for solar thermal power, by and large it has been eclipsed by solar PV in recent years, with solar panel prices plummeting and manufacturing capacity surging. While thin film solar has also become competitive it is traditional silicon based solar PV that has dominated after years of being dismissed as being too expensive.

Research into improving solar PV remains vibrant, with new materials and concentrating solar power techniques looking to push the cost of solar PV below that of coal or gas fired power (the holy grail of solar grid parity).

Wind power

Wind power is the second largest renewable energy source available to us, with the potential supply also exceeding current global energy demand.

Wind power has also seen rapid growth over the past decade, with generation increasing by over 18% in 2012 and accounting for more than half of new renewable energy supply. In Denmark it now supplies more than 28% of electricity consumption.

Wind power is now the cheapest source of renewable energy, with the LCOE being competitive with coal or gas fired power in many locations. Thanks to the merit order effect, wind power can also help lower the cost of power paid by consumers. While wind power is now a relatively mature technology, advances in turbine size and electromagnet technology along with optimisation of wind farm sites are allowing the overall efficiency of generation to increase further.

Like solar power, wind power can coexist with other uses of land - and large wind farm developments can also be located offshore.

Also like solar power, wind power is criticised for its intermittency. While geographical diversity of generation (along with diversity of energy sources and expanded grids, which will be discussed later) can help to address this, energy storage can also be built into wind turbines, a technique used in new models from GE.

Hydro power

Hydro power is the most mature source of renewable energy (the burning of wood aside) and still accounts for more electricity production than solar, wind, and geothermal combined - however it has a growth rate (around 3% in 2012) lower than most other renewables.

Hydro power current provides 16% if global power generation - the 4 largest power stations in the world are all hydro power projects.

Large scale hydro power doesn't have a lot of room for growth in the developed world, though the Himalayan region and Africa both still have significant room for growth.

Microhydro power is an alternative that is underdeveloped and often has an LCOE quoted that makes it competitive with wind power and with fossil fuels - however I've never seen any useful figures outlining the energy potential from this source (if you look at some designs you'd guess that this is something that could be deployed very widely).

Geothermal power

Geothermal energy is unusual compared to other large renewable power sources, in that it provides "baseload" power (thus placating those suffering from the "baseload fallacy") unlike other more intermittent sources like solar, wind and ocean power. The potential supply of geothermal energy is approximately equal to current global energy demand.

The first geothermal power generation plant was constructed in 1904 in Larderello, Italy, followed by Wairakei, New Zealand in the 1950's then the Geysers in California in the 1960’s. In 2012, 24 countries operated geothermal plants for electricity production, generating around 12 GW in total.

In 2012, growth in geothermal power was less than 3%, leaving it very much a niche energy source. Geothermal power generation is currently concentrated in geologically active areas - the western US, Indonesia, The Philippines, New Zealand, Iceland, Costa Rica, El Salvador and east Africa.

As well as active power generation from traditional geothermal power sources (including low temperature geothermal), ground source heat pumps can be used to provide direct heating.

The great white hope for geothermal power generation is known as "Enhanced Geothermal System" (EGS) (or sometimes Hot Dry Rock or Hot Fractured Rock) - generating power by drilling holes deep into the earth's crust to circulate water through. The energy potential for this type of geothermal energy is vast, however progress so far in terms of producing commercial power has been very disappointing.

Some early experiments were built in Switzerland but have been shut down due to concerns about earthquakes being caused by the drilling. The most promising experiment is being performed by GeoDynamics in Australia's outback - progress has been extremely slow, with numerous setbacks occurring before a 1 MW pilot plant was finally commissioned this year. On a positive note, operation of the pilot is beating expectations.

Ocean energy

Energy can be tapped from the oceans in 3 different ways - tidal power, wave power and the little known OTEC (Ocean Thermal Energy Conversion).

While there is a significant potential resource in ocean energy - broadly equivalent to our current energy use - the technology for exploiting all 3 forms of energy remains immature and costly. Tidal power has been commercially generated since the 1960's, with France's 240 MW "La Rance" power station only recently being eclipsed in size by a South Korean project. South Korea is looking to greatly expand tidal power production over the next 5 years and a range of projects are proposed for the UK, Australia and the United States - however it appears unlikely that we will see large scale tidal power production in the next couple of decades.

Wave power and OTEC are even less advanced, however pilot projects are at various stages of development for both of them and interest will no doubt slowly build in size over time. Another even more exotic alternative is the generation of electricity using differences in salinity between bodies of water.

Biomass, Biogas and Biofuel

Photosynthesis provides a steady stream of material that can be used for energy - with the caveat that there are limits before this impacts on our ability to produce food and maintain a healthy environment.

There are a range of ways of harnessing organic material for energy (other than the traditional approach of burning it for heat - which the REN21 (pdf) report on renewable energy notes is still the dominant use for biomass - contributing almost 7% of global energy supply) - using biomass to generate power, producing biogas which can be used for heat, power generation or for transport, producing biofuels that can replace or supplement traditional liquid fuels and for pyrolysis which can generate biodiesel, fertiliser and biochar.

Biofuels have been the subject of widespread criticism (critics citing competition with food production and low EROI) and seem unlikely to be able to replace a significant proportion of our oil consumption. Production of ethanol and biodiesel has stagnated in recent years, with production declining by 0.4% in 2012.

Other advanced biofuels such as cellulosic ethanol and algae based biofuels have failed to be produced in significant quantities thus far.

Biomass based power generation also has its critics, though most seem to agree that it is preferable to biofuel production. Global biomass power generation capacity was 58 GW in 2011 and is expected to grow to 86 GW by 2021. The industry seems to be suffering some headwinds, with the largest biomass power plant (Tilbury in the UK) recently being mothballed. Another large scale project in the UK (Drax) still seems to be going ahead, and generation of power from waste is booming in Europe.

Biogas is the most promising of the biomass based energy generation approaches, with far fewer criticisms being leveled at it (most importantly, there is limited competition between food production and biogas production - the two are often complementary in fact - and the net energy available from biogas far exceeds that of biofuels). It can either be extracted from landfills or produced using "digesters" that process agricultural waste (or occasionally by exploiting natural sources of biogas).

The upper limits for biogas production are not clear, though some studies claim vast amounts can potentially be produced - for example, one European study said that all of Europe's gas needs could be met with biogas. Biogas power generation apparently produced about 14.5 GW in 2012.

Biogas is not only the most environmentally friendly of the biomass based energy alternatives it is also the most versatile, with the gas being able to be used for heat, power (or a mix of both - combined heat and power) or transport.

One last use for biomass is the production of biochar. Producers of biochar take dry biomass and bake it in a kiln to produce charcoal. Biochar is the term for what is left over after the energy is removed: a charcoal-based soil amendment. This process is called pyrolysis. Various gases and oils are driven off the material during the process and then used to generate energy. The charcoal is buried in the ground, sequestering the carbon that the growing plants had pulled out of the atmosphere. The end result is increased soil fertility and an energy source with negative carbon emissions.

Distribution of renewable energy

Smart Meters and Smart Grids

Renewable energy (primarily solar and wind power) is often criticised for being intermittent.

In the traditional model of electricity generation and distribution, large, centralised power stations were built with sufficient capacity to handle expected peaks in demand - with significant amounts of capacity idle during non peak parts of the day / year (and brownouts occurring if demand did happen to exceed supply). Consumers were charged a regulated price that ignored fluctuations in supply and demand - instead supply was adjusted as far as was practicable to meet demand.

Adopting a more dynamic (market based) pricing mechanism would allow energy users to have an incentive to shape their energy use to the available supply, thereby enabling fluctuations in supply to be dealt with.

The keys to making this possible are to provide electricity consumers with smart meters and the ability to alter their energy usage based on market price fluctuations. Smart grids are required for electricity distributors to create a more flexible grid incorporating a much more diverse range of power generators.

Supergrids and The Global Energy Grid

As well as making the grid more dynamic, interconnections between grids need to be expanded to enable a greater diversity of suppliers to be available across a wide region - this helps further address the issue of intermittency of supply - the sun may not be shining and the wind may not be blowing in one region however this won't be true across all regions making up a greater grid.

Proposals for extending regional grids into continent wide ones (usually by building HVDC connections between existing grids) tend to be dubbed "supergrids" - examples can be found for North America, Germany and the whole of Europe and between Europe and North Africa.

Buckminster Fuller took this idea to its logical endpoint and recommended the creation of a "global energy grid" as a step towards ending our dependency on fossil fuels.

Energy Storage

The final piece of transforming the electricity grid to distribute 100% renewable energy is building in sufficient energy storage to ensure that suppliers have the ability to react to swings in demand as well as vice versa.

Traditionally energy storage has been available in greater or lesser amounts (depending on what grid you are connected to) in the form of pumped hydro storage.

A wide range of other options have been proposed and explored over the years, ranging from Compressed air energy storage to batteries to flywheels to generating hydrogen (pumped hydro even has an ocean equivalent which is one of the more promising options).

Most battery storage being implemented today involves either lithium ion batteries or flow batteries - however further cost reductions are viewed as being necessary to enable wider availability of energy storage services.

One option receiving a lot of attention recently has been a proposal by MIT Professor Donald Sadoway to build liquid metal batteries.

Adopting alternatives to oil

While it is clear that we can replace all the energy we currently get from fossil fuels with renewable energy, the problem remains that electricity is not a direct substitute for liquid fuels - and that fossil fuels have some other important uses other than providing energy.


The most important use of liquid fuels is in transport. Increasing fuel efficiency of vehicles (around 3% per year) and substitution of natural gas for oil as a fuel for heavy vehicles has been constraining the growth of oil consumption for road transport in recent years, however this can only ever be a temporary solution - in the longer term we need to use either electricity or (in limited circumstances) biofuels.

Electrifying as much of the transport system as possible is the first step, with biofuels being used for those forms of transport that cannot be electrified (either liquid biofuel such as ethanol or biodiesel, or compressed biogas) such as large planes and ships.

Hybrid electric vehicles (including plug in hybrids and solar hybrids) are a maturing technology with over 5 million vehicles on the roads now.

These are providing the stepping stone to fully electric vehicles (which are already outselling plug in hybrids in the US). The journey towards fully electric cars has been a slow one with the star example so far being Tesla Motors (other promising projects such as Better Place have fallen by the wayside in recent years, though manufacturers such as Nissan are competing at the lower end of the market and a raft of car makers are building high end electric sports cars).

Three problems are holding up the transition to electric vehicles at this point - slow recharge times, "range anxiety" and the relatively high cost of electric vehicles compared to legacy internal combustion engine based vehicles. Tesla are looking to address both of the first two issues by pursuing both fast recharge technology (with various other schemes being implemented around the globe) and a battery swap system similar to that pursued by Better Place.

The IEA has set a target of 20 million electric vehicles by 2020, with further 50% increase in battery performance a key to achieving this goal, following on the 50% increase achieved in the past 3 years.

Cars aren't the only type of vehicle that requires fuel of course - heavier forms of of transport also consume oil. We are now starting to see electric trucks, electric buses and electric boats begin to appear out in the marketplace. Where heavy vehicles such as buses follow the same route on a regular basis they become candidates for recharging while in transit.

Of course, we don't have to simply substitute electric vehicles for existing liquid fuel powered ones. There is a wide range of alternatives available including:

  • Walkable communities
  • Cycling. Many journeys do not need to be made by car, particularly if cities are designed to enable transport by cycle (both by pedal powered bicycles and electric bikes) as well as by foot or rail transit.
  • Transit oriented development
  • Rail transport. Rail transport can be electrified where it isn't already and can provide both transit within cities and long distance travel as well (preferably via a high speed rail network)
  • Exotic options such as Personal rapid transit and Elon Musk's proposed Hyperloop


Nearly all the plastics sold today come from petroleum, accounting for up to 5% of global petroleum consumption by some estimates. Recycled plastics are a good first step towards reducing oil consumption, however they can only be recycled two to four times, and only around 25% of plastics are actually recycled.

The sustainable alternative to traditional plastic is bioplastic. The cost of producing bioplastic has been falling thanks to improved processes, requiring lower temperatures. Combining this with the increasing cost of crude oil has made bioplastic prices competitive with regular plastics.

Bioplastic production is expected to reach 1 million tons in 2015, out of total global plastics production of around 300 million tons.

Leading manufacturers include Avantium, BASF, Braskem, Cereplast, Metabolix and Natureworks. Bioplastic feedstocks include vegetable oil, corn starch, plant cellulose and mycellium.

Bioplastic doesn't necessarily need to replace all current uses of plastic - other alternatives are materials that have been replaced by plastics in recent decades, including steel, wood, aluminum, glass, cardboard and paper.


Agriculture obviously requires transport to grow and distribute food products, however it also requires fertiliser (at least if we continue to follow the green revolution model), which is usually produced using natural gas.

This can be addressed via a range of techniques - by being more efficient with fertiliser use (which would have many environmental and health benefits), by adopting organic farming techniques, by growing food near where we live, by generating ammonia using air, water and renewable energy - or by getting to the root of the problem and enabling plants to fix nitrogen themselves.

Another way of reducing energy consumption from agriculture is to find new ways of producing food - efforts to produce artificial meat (or "cultured beef", as it is sometimes known) have the potential to reduce the amount of energy required to produce meat by 45%.

Manufacturing and Construction

Manufacturing is a major consumer of energy and raw materials. The amount of energy and other raw materials devoted to manufacturing can be reduced by optimising for recycling - in particular by adopting "cradle to cradle" design and manufacturing techniques.

Distributed manufacturing and 3D printing also have potential for reducing the amount of energy required to distribute manufactured goods.

The construction and ongoing operation of buildings is another major consumer of energy, with "green buildings" and energy efficient devices such as LED lighting that minimise energy consumption being an important part of our clean energy future.


The aim of this post was to demonstrate the following (or at least provide food for thought to irredeemable skeptics) - I hope you've found it thought provoking.

  • There is more than enough renewable energy available to meet all our needs - primarily using solar and wind power - and this can be done at a reasonable cost
  • The keys to shifting to renewable energy are to expand the interconnectedness of our electricity grids, to make electricity demand more dynamic (responding to changes in electricity supply / price) and to put more energy storage in place
  • That we need to be aware of the areas where we use fossil fuels and transform these to use renewable energy - to electrify our transport systems, to adopt alternatives to traditional plastics and to adapt our agricultural, manufacturing and construction processes to reduce the amount of energy required and to eliminate dependencies on fossil fuels

Sunday, April 19, 2009

Space Based Solar Power ?

Californian utility PG&E caused a stir in the media recently with an announcement that they are seeking approval from state regulators for a power purchase agreement with Solaren Corp. to deliver 200 MW of power by 2016 for a 15 year period.

Californian utilities have been signing deals with a wide range of renewable energy providers in recent years in order to meet the state's mandated clean energy targets - the unusual aspect of this announcement is that Solaren is proposing to generate the power using solar panels in earth orbit, then convert it to radio frequency energy for transmission to a receiving station in Fresno County where it will be fed into the grid.

PG&E's Next 100 blog has an interview with Solaren CEO Gary Spirnak, in which he claims that while this will be the world's first SSP plant, and no system of this scale and exact configuration has been built before, the "underlying technology is very mature and is based on communications satellite technology".

PG&E has promised to buy the power at an agreed-upon rate (comparable to the rate specified in other agreements for renewable-energy purchases) according to company spokesman Jonathan Marshall, however neither PG&E nor Solaren are saying what that rate is. PG&E is not making an up-front investment in Solaren's venture.

PG&E's interest in this sort of ambitious project is prompted by California's mandates to obtain 20 percent of its electricity from renewable sources by 2010 and 33 percent by 2020.

The benefits of space based solar power

If Solaren (or other companies pursuing similar ambitions, such as Heliosat, Space Energy, Space Island Group, Powersat and the Welsom Space Consortium) can collect solar energy in space and transmit it to earth they will have opened up a significant new energy resource. The sun's energy is almost continuously available to a satellite located in a geosynchronous orbit about the earth (leading promoters of space based solar power schemes to dub it "baseload solar power").

A 2007 study by the Pentagon’s National Security Space Office which included representatives from DOE/NREL, DARPA, Boeing and Lockheed-Martin found that a one-kilometer-wide band of space in earth orbit receives enough solar energy in just one year (approximately 212 terawatt-years) nearly equal to “the amount of energy contained within all known recoverable conventional oil reserves on Earth today” (approximately 250 TW-yrs). The Pentagon study suggested such a system could be tested as early as 2012, with the likely first customer being the US military.

There are a number of key advantages that make space based solar power an interesting alternative to ground-based solar power:
  • There is more energy to be collected - the sun is more intense in orbit than on the surface of the Earth
  • Space based systems can collect energy almost around the clock
  • Ground-based systems suffer from weather phenomena such as clouds, precipitation, and dust - space based system do not (though the increasing amount of junk in orbit poses a similar hazard)
  • Real estate costs are minimal - the only land that need be acquired is the land for the receiving station.
  • Transmission line costs are greatly reduced compared to remote generation facilities if the ground station is located near existing transmission lines

The video below is from the National Space Society, showing what a space based solar plant might look like.


There are 2 primary challenges to making space based solar a reality.

The first is the technological challenge of making a scheme like this work - this is not been so much converting solar energy into radio frequencies (which has been done before, though not on Solaren’s scale) - but in getting a supersized solar array into space and successfully commissioning it.

The second challenge is one of economics - can the cost involved in building a solar power plant in space ever be competitive with ground based concentrating solar thermal, regular solar PV or thin film solar power plants.

Plans for space based solar have traditionally included kilometre long structures of solar arrays connected to satellites, and launching thousands of tons of heavy metal into orbit is exorbitantly expensive.

Solaren's Spirnak says he has a solution - “We want to take the weight out of these systems. We came up with this design concept to break these things into pieces instead of trying to construct many, many kilometers of structures in orbit, which would essentially be unbuildable.”

Instead, his station will consist of two to four components that will float free in space (kept in alignment by software controls and small booster rockets rather than heavy wires, cables and struts). According to Solaren’s patent, an inflatable Mylar mirror a kilometer in diameter will collect and concentrate sunlight on a smaller mirror that will focus the rays on the solar array. By adopting a concentrating solar power approach, a smaller and lighter array can be deployed, reducing the cost of lifting the components of the structure into orbit.

At this point there is little information about cost available for Solaren's proposal, though Grist quotes Spirnak as saying the price tag for the 200-megawatt solar power station for PG&E will be “in the several billion dollar range” and will require 4 or 5 rocket launches.


The concept of space based solar power was first proposed in 1941 by science fiction author Isaac Asimov in his book “Reason,” about a space station that collects solar energy and beams it to Earth.

Wikipedia's article on the topic includes a good timeline of developments in the field, noting that Dr Peter Glaser was granted a US patent in 1973 for his "method of transmitting power over long distances (eg, from an SPS to the Earth's surface) using microwaves from a very large (up to one square kilometer) antenna on the satellite to a much larger one on the ground, now known as a rectenna".

Asimov continued to promote the idea throughout his life, with this talk (part 1, part 2) on "Threats To Humanity", delivered to The Humanist Institute In New York in 1989, in which he described the threats of global warming and fossil fuel depletion, and recommended the solution as space based solar power whose delivery is managed by a federal world government / "stable world order".

ANother peak oil observer who has regularly promoted the idea of space based solar power is JD at Peak Oil Debunked, who has looked at the idea of solar power plants based on the moon a number of times (Lunar Solar Power, More on Lunar Solar Power).


Another space based energy panacea, using helium 3 from the moon to fuel fusion reactors, has caused some cynics to mutter that this is just a scheme to funnel large amounts of funds to well connected aerospace companies. I suspect that similar charges will be laid against spaced based solar power plans until the economics of them can be proven to match those of terrestrial renewable energy projects.

The authors of the Pentagon report mentioned earlier noted that space based solar “has the potential to be a disruptive game changer on the battlefield ... [enabling] entirely new force structures and capabilities such as ultra long endurance airborne or terrestrial surveillance or combat systems” - which implies that there might be more than one reason for wanting to deploy space based solar power - like the symbiosis between nuclear weapons development and the nuclear power industry, it may be that space based solar power provides a civilian friendly reason for building 'star wars" type platforms in space.

Cryptogon has some speculation along these lines, and goes on to wonder if this is another possible example of the introduction of technology developed in "black" military projects (there is a section in my "Shockwave Rider" review that talks about the 5000 secret patents registered by the USPTO) into the civilian sector (echoing his speculation about the role of the new GM CEO appointed by the Obama administration).

Another skeptic commenting on the Solaren proposal at Peak Energy wondered cynically if this was a form of greenwashing by PG&E, saying "This is an opportunity for PG&E to get some free green publicity and "demonstrate" their interest in meeting their RPS requirements. When the power doesn't appear in 2016, they can just throw up their hands and say "we tried, not our fault"."

Most skeptics focus purely on the economics though, with the Motley Fool declaring Space-Based Solar? That's Just Silly and Energy & Capital asking "Why would anyone be interested in space-based solar power when commercial utility scale solar technology on the ground today costs 0.3% of its price?" in The Solar Race Will Be Lost in Space.

Monday, December 8, 2008

Floating Offshore Wind Power

Matthew Simmons has received quite a bit of press in the past week, after his Ocean Energy Institute floated a proposal to build a $25 billion, 5 GW wind farm in the Gulf of Maine.

Offshore wind farms have a number of advantages over their land based equivalents - they are less hazardous to wildlife, have fewer objections raised on NIMBY concerns and winds are generally stronger over the oceans than they are over land.

Ideally, offshore wind farms will be far enough away from land to avoid being seen from the shoreline, eliminating any residual objections from local residents. Current offshore projects tend to site turbines in waters less than 20 metres deep - going further offshore would mean locating them at depths of 50 meters or more, which is too deep to build supporting towers or trusses down to the sea floor at an affordable cost.

A solution to this problem is floating platforms - one of the key elements of the Ocean Energy Institute proposal. In this post I'll look at some of the work being done to develop floating offshore wind power platforms in order to enable these sorts of schemes to become a reality.

Floating Wind Turbines

According to a 2006 report by the U.S. Department of Energy, General Electric and the Massachusetts Technology Collaborative, offshore wind resources on the Atlantic and Pacific coasts of the United States exceed the current electricity generation of the entire U.S. power industry. NASA has also been investigating ocean wind strengths worldwide, using the QuikSCAT satellite.

Researchers at MIT and elsewhere have been investigating the feasibility of "tension-leg" platforms for wind turbines, a technology that oil companies have been using for deep-water rigs. The structures would be assembled at a shipyard and placed on large floating cylinders that are ballasted with high-density concrete (to keep the structure from tipping over) and then tugged out to sea. Once in location, steel cables would be attached to the platform, anchoring it to the sea floor.

The MIT researchers claim that large turbines located far offshore could eventually generate cheaper power than both land based wind farms and near-offshore ones (even taking into account the increased cost of longer underground electricity transmission cables). Part of the cost advantage is the higher capacity factor achieved due to more consistent offshore winds - potentially averaging between 40 percent and 50 percent compared with 30 percent or less with land based turbines.

Some offshore wind farms could also have advantages in terms of proximity to large coastal cities compared to wind farms in remote areas, which require grid transmission upgrades to transport the power to places where it is consumed. Floating offshore wind farms also avoid bottlenecks in the supply of marine construction equipment such as pile drivers and cranes that may hamper rapid expansion of shallow offshore wind structures (however they may instead compete for some resources with offshore oil exploration and production, which could be problematical in the short to medium term).

A number of companies are active in the area of floating offshore wind technology - primarily Blue H Technologies, StatOil Hydro and SWAY.

Blue H Technologies

Blue H Technologies is a Dutch company that launched their first test platform at Tricase off Italy's southern coast late last year. The company has also announced plans to install another test turbine off Massachusetts.

The Blue H test platform in Italy is a tension-leg platform - a conventional offshore oil and gas platform design that floats below the surface, held in place by chains running to steel or concrete anchors on the seabed. The platform is located 10 km offshore and hosts an 80-kilowatt wind turbine which is mounted with sensors to record the wave and wind forces experienced by the equipment.

Blue H is now constructing a commercial wind farm for the Tricase site, which will have an installed capacity of 92 MW.

Blue H's design is unusual in that the turbine has a two-bladed rotor rather than the conventional three-blade design used elsewhere in. Technology Review has quoted Martin Jakubowski, Blue H cofounder and chief technology officer, as saying that "the noise and jarringly high rotation speeds that made two-bladers a loser on land are either irrelevant or a plus offshore" and that the fast rotation is "less susceptible to interference from the back-and-forth swing of the platform under wave action" and means less torque, resulting in a lighter structure (Blue H's 2.5-megawatt turbine will weigh 97 tons - 53 tons lighter than the lightest machine of the same power output on the market).

Tech Review also quotes Jakubowski as estimating that Blue H's wind farms will "deliver wind energy for seven to eight cents per kilowatt-hour, roughly matching the current cost of natural gas-fired generation and conventional onshore wind energy".

StatOil Hydro

Norwegian oil and gas producer StatoilHydro and Germany's Siemens (a major wind-turbine producer) are partnering in a project to build a commercial-scale floating wind farm about 10 kilometers offshore from Karmøy on Norway's southwestern tip.

StatoilHydro initially plans to operate a 2.3 MW wind turbine atop a conventional oil and gas platform, and is hoping for this to be operational in late 2009. Unlike the Blue H design, StatOilHydro is using traditional wind turbines.

The company believes floating wind farms are the way of the future, with a company spokesman saying that there are a declining number of sites available onshore and in shallow waters and citing regions without a shallow continental shelf like California, Japan and Norway where traditional offshore wind is not possible.

StatOilHydro says that deepwater wind power will be expensive in the initial stages but that the economics could eventually rival those of conventional wind power.

If deep offshore wind power in the North Sea proves to be successful it would become a major component on the planned European Supergrid, which backers hope will link up the region's power networks and allow a much higher proportion of renewable energy in future (possibly entirely fossil-free, as it will need to become eventually).


SWAY, based in Bergen, Norway, plans to field a prototype of its floating wind turbine in 2010. SWAY's platform is basically a spar buoy that can rise and fall gently with wave action, requiring less anchoring than the tension-leg platform. The buoy, mounted on a column nearly 200 meters tall, is held in place by a 2,400-ton gravel ballast. A three-bladed turbine is used, but, unlike conventional onshore turbines, it faces downwind rather upwind to better accommodate heeling of the tower, which may make it more effective in rougher waters than alternative designs.

The Simmons Plan

The cost estimated for Simmons' plan is $5 billion per gigawatt — more than double the amount that T. Boone Pickens’ now delayed wind farm in Texas is supposed to cost.

This seems high if the cost savings expected by the companies mentioned above eventuate, with the StatOilHydro experiment probably being the best guide, with the North Sea facing similar weather challenges to those experienced off New England.

Winter winds in the Gulf of Maine carry as much as eight times more energy as summer breezes, meaning maximum power is available during periods of greatest demand. About 80 percent of Maine residents use oil to heat their homes. The average family uses about 1,000 gallons, or 3,785 liters a year - when prices are around $4 a gallon ($1 a litre) this consumes about one-tenth of the average family's annual income, leading Simmons to declare "If we don't do this, we're [eventually] going to have to evacuate most of Maine".

Seen in that light, even an expensive offshore wind farm is better than the alternative.

As an added bonus, construction and maintenance of the structures will bring valuable job opportunities to a region hard hit by the decline of the fishing industry.

Related Posts :

The Oil Drum - Alternative Wind Power Experiments - SkySails and Airborne Wind Turbines (Peak Energy)

The Oil Drum - Offshore Wind

Tuesday, November 25, 2008

Low Temperature Geothermal Power

The ABC recently had a report on plans to power north-west Queensland with low temperature geothermal power using hot water from the Great Artesian Basin.

A Brisbane-based company says it could supply geothermal power to all of north-west Queensland. Clean Energy Australasia wants to build a $50 million geothermal power station near Longreach. But it has now also revealed plans to build a pilot geothermal project near BHP's Cannington mine at McKinlay, south of Cloncurry. The company's Joe Reichman says the Mount Isa region needs about 500 megawatts of power a year and geothermal resources could easily provide that. "It'll change the region into a powerhouse," he said. Mr Reichman says the company has applied for federal and state government grants and has support from the major mining companies in the region. If the projects proceed they would be the first geothermal power plants in Australia.

Low temperature geothermal power is a relatively new (and very low profile) form of extracting energy from geothermal sources that provides yet another option for meeting our energy needs cleanly and sustainably.

Low Temperature Geothermal Power

When geothermal power is mentioned, people usually think of traditional high temperature geothermal power stations using water from volcanic areas, such as those found in Iceland, New Zealand, the US and elsewhere around the ring of fire.

More recently, interest in enhanced / engineered geothermal systems (EGS) - also known as hot dry rock (HDR) or hot fractured rock (HFR) geothermal power - has been high, with a number of experimental projects underway in Australia and Europe.

Low temperature geothermal power is also starting to attract significant interest, as lower temperature water resources are common in many countries (for example, waste hot water produced by oil and gas wells - in Texas alone, more than 12 billon barrels are produced, with oil companies usually re-injecting the waste water into the earth) and new technologies are beginning to appear that allow these resources to be developed commercially.

UTC Power has developed a low-cost Rankine cycle system that can convert temperatures as low as 195 °F (91 °C) into electricity. The technology is similar to a steam engine, with steam or hot water vaporizes a hydrofluorocarbon refrigerant that drives the turbine (it has been compared to a "refrigerator compressor running backwards").

Geothermal Power In The Great Artesian Basin

The Great Artesian Basin provides the only reliable source of water through much of inland Australia. The basin is the largest and deepest artesian basin in the world, covering a total of 1,711,000 square km. It underlies 23% of the continent, including most of Queensland, the south-east corner of the Northern Territory, the north-east part of South Australia, and northern New South Wales. The basin is 3000 metres (10,000 ft) deep in places and is estimated to contain 64,900 cubic kilometres of groundwater.

Most recharge water enters the rock formations from relatively high ground near the eastern edge of the basin (in Queensland and New South Wales) and very gradually flows towards the south and west. Because the sandstones are permeable, water gradually makes its way through the pores between the sand grains, flowing at a rate of one to five metres per year. Discharge water eventually exits through a number of springs and seeps, mostly in the southern part of the basin. It takes up to two million years for water to travel to the springs in the Lake Eyre area.

Temperatures of the artesian groundwater (which is generally of a very good quality) range from 30o to 100o C at the well heads. As the groundwater is too hot for town water supply and for stock to drink, it needs to be cooled down before consumption. That is why cooling towers can be seen throughout the region.

The ABC report's claim that the Longreach plant would be Australia's first geothermal power plant is incorrect.

A small (120 kW) power station (pdf) has been in operation at Birdsville in western Queensland since the early 1990's - one of the few low-temperature geothermal power stations in the world. The plant derives its energy from the near-boiling (98 degrees C) water taken from the Great Artesian Basin (at a depth of 1230m) that provides a water supply for the town. Operation of this geothermal power station reduced the town's diesel consumption by about 160,000 litres per year.

The Victorian town of Portland (in the Otway Basin) also operated a district heating scheme using water from geothermal sources for about 20 years, though this did not generate power.

Geothermal Power In The United States

The UTC plant has been trialled at the Chena Hot Springs in Alaska, with the first plant going online in July 2006. A second unit began operating later that year. Together, the two power units are contributing to the resort owner's goal of making Chena the first totally renewably powered and fueled community in the United States. The Chena experience is motivating other cities in Alaska, including Anchorage to investigate setting up larger scale geothermal plants.

UTC installed more production systems at another location in New Mexico in August this year.

Utah company Raser Technologies is looking to build a range of geothermal power plants throughout the western United States using Rankine cycle systems, with their first plant going live in Utah earlier this month.

Some oil fields also produce hot water which can be used to drive Rankine cycle power plants, with trials being performed in Wyoming.

Geothermal Power In Germany

Germany is interested in deriving significant amounts of energy from both EGS / HFR and low temperature geothermal sources. There are already four small geothermal power plants successfully operating in Germany, albeit supplying only a tiny amount of electricity.

The first geothermal plant to start operating in Germany is situated in Neustadt-Glewe in the north-eastern part of the country. The 230-kW combined electricity and heat power plant started up in 2003 and extracts water with a temperature of 97 °C from a well 2250 meters under the ground. It supplies 1,300 households with heat and a further 500 households with electricity.

Other plants now operating are the 3.5-MW plant at Unterhaching close to Munich, in Bavaria which is the first geothermal plant in Germany to use Kalina cycle technology. At that plant water is extracted at a temperature of 122 °C from a well 3,500 meters deep. Another 2.5-MW plant in Landau taps water of 150°C that is located 3,000 meters beneath the ground. Another 550-kW plant is due to go into operation in Bruchsal shortly, extracting water at temperatures of 128°C from a well 2500 meters deep.

More plants (as big as 8-10 MW) are due to go into operation in 2009-2010 in Sauerlach, Dürrnhaar, Riedstadt, Speyer, Gross Schoenebeck and Mauerstetten. By 2015 there could be more than a hundred plants operating - around 150 geothermal power plant projects are in the pipeline according to the German government. One major constraint on expanding the program has been shortages of drilling equipment.

Geothermal Power In New Zealand

While New Zealand already generates a significant portion of its power using traditional geothermal sources, the country is also conducting a NZ$2.6 million research program into low temperature geothermal power.


Low temperature geothermal power has the advantage of being clean, continuously available energy that can be generated in a wide variety of locations.

Plants will likely to continue to be relatively small-scale, making it a classic distributed energy generation alternative (like biogas and solar PV), with growth probably remaining low profile for some time.

In the long run, I expect we'll see a useful and significant amount of our energy needs being produced using this technology.

Saturday, November 1, 2008

Making Australia A Better Place

Project Better Place founder Shai Agassi was in town last week announcing that Australia will become the third country to implement the group's vision of electric vehicles powered by renewable energy, following Denmark and Israel.

Better Place and Macquarie Capital Group will raise $1 billion to build a network of 250,000 charging stations and battery exchange stations in key locations along the east coast by 2012. The network will be powered by wind turbines owned by AGL Energy.

Agassi has been promoting the plan as a way to reduce our dependence on oil (the starting premise for the project was "how do you run an entire country without oil") while creating jobs and boosting the local economy (see this interview on the Today Show for his explanation). Operating in Australia will also help the group prove it can work in large countries as well as the much smaller geographical areas covered in the first 2 rollouts. Agassi also noted that the Federal Government's $500 million Green Car Innovation Fund played a part in encouraging them to set up in Australia.

Green Car Congress describes the Better Place network as consisting of three primary components:
  • Charge points. These are to charge batteries with power, providing 160 kilometres of driving range, according to the company. Better Place is planning a 2.5:1 ratio of charge spots to cars.

  • Battery switching stations. For trips longer than 100 miles (161 km), Better Place plans to build roadside battery switching stations. Stations are to be completely automated, and the driver’s subscription takes care of everything. The driver pulls in, and the depleted battery is replaced with a fresh one, without anyone having to leave the vehicle. The process takes less time than it does to fill a tank of liquid fuel, according to the plan.

  • Software to automates the charging and exchange process.

Better Place has a partnership with the Renault-Nissan Alliance to provide electric cars. The prototype electric eMegane sedan features a 160+ kilometre range.

Better Place says it is committed to open network access and using industry standard, with the goal being to allow customers to have a choice of make and model of car.

Automotive Energy Supply Corporation (AESC, a joint venture between Nissan Motor, NEC Corporation, and NEC TOKIN Corporation) and A123Systems have been identified as lithium-ion battery providers to the system.

Better Place plans to own and operate the batteries and power generation (via AGL Energy, in Australia's case), and to sell kilometres travelled to drivers on a subscription basis, in similar fashion to the mobile phone industry.

Better Place in Australia plans to start by setting up charging stations in the Melbourne, Brisbane and Sydney, and then connect them with "electric highways," with stations set up every 25 miles.

Overall I'm quite excited by this project - though obviously executing the plan, in terms of setting up all the infrastructure and getting a significant volume of electric cars on the market at a competitive price, will be challenging. If the 3 countries piloting the idea can demonstrate it can work successfully, it will provide a blueprint for personal transport in a post-oil world.

Friday, September 12, 2008

Terra Preta: Biochar And The MEGO Effect

This month's edition of National Geographic has a feature article on "Soil", which looks at the steady degradation of agricultural land and the problem this poses in world where the population is heading for 9+ billion people - effectively calling attention to the "peak dirt" problem (however soil is renewable, so any "peak" should be able to be reversed if sufficient time and effort is put into doing so).

The article uses an acronym I've never come across before to describe the problem faced by those trying to draw attention to the issue: MEGO (My Eyes Glaze Over) - a phenomenon which should be familiar to anyone who has ever talked about peak oil, global warming or any of the other "limits to growth".

This year food shortages, caused in part by the diminishing quantity and quality of the world's soil, have led to riots in Asia, Africa, and Latin America. By 2030, when today's toddlers have toddlers of their own, 8.3 billion people will walk the Earth; to feed them, the UN Food and Agriculture Organization estimates, farmers will have to grow almost 30 percent more grain than they do now. Connoisseurs of human fecklessness will appreciate that even as humankind is ratchetting up its demands on soil, we are destroying it faster than ever before. "Taking the long view, we are running out of dirt," says David R. Montgomery, a geologist at the University of Washington in Seattle.

Journalists sometimes describe unsexy subjects as MEGO: My eyes glaze over. Alas, soil degradation is the essence of MEGO.

One subject that features in the article is soil restoration, including a look at "terra preta" - rich, fertile artificial soils found in the Amazon. In this post I'll have a look at modern day techniques to produce terra preta (often called biochar or agrichar) which have the potential to increase soil fertility, generate energy and sequester carbon all at the same time.

The History Of Terra Preta

Terra Preta ("dark earth") was discovered by Dutch soil scientist Wim Sombroek in the 1950's, when he discovered pockets of rich, fertile soil amidst the Amazon rainforest (otherwise known for its poor, thin soils), which he documented in a 1966 book "Amazon Soils". Similar pockets have since been found in other sites in Ecuador and Peru, and also in Western Africa (Benin and Liberia) and the Savannas of South Africa. Carbon dating has shown them to date back between 1,780 and 2,260 years.

Terra preta is found only where people lived - it is an artificial, human-made soil, which originated before the arrival of Europeans in South America. The soil is rich in minerals including phosphorus, calcium, zinc, and manganese - however its most important ingredient is charcoal, the source of terra preta's color.

It isn't entirely clear if the Amazon Indians whose old settlements terra preta is found at deliberately created the soils or if they were an accidental by-product of "slash and smoulder" farming techniques, though the emerging consensus seems to be that the Indians deliberately created the material, with some early European accounts in the area noting the practice still being performed.

The key ingredient is apparently the activated carbon in the charocal. Activated carbon has a complex, spongelike molecular structure - a single gram can have a surface area of 500 to 1,500 square meters (or about the equivalent of one to three basketball courts). Having this material in the soil has several beneficial effects, including a 20% increase in water retention, increased mineral retention, increased mineral availability to plant roots, and increased microbial activity.

It has also been shown to be particularly beneficial to arbuscular mycorrhizal fungi, which form a symbiotic relationship with plant root fibers, allowing for greater nutrient uptake by plants. There is speculation that the mycorrhizal fungi may play a part in terra preta’s ability to seemingly regenerate itself.

Pyrolysis and Eprida

Modern day producers of biochar (agrichar) take dry biomass and bake it in a kiln to produce charcoal. Biochar is the term not for what is left over after the energy is removed: a charcoal-based soil amendment - this process is called pyrolysis. Various gases and oils are driven off the material during the process and then used to generate energy. The charcoal is buried in the ground, sequestering the carbon that the growing plants had pulled out of the atmosphere. The end result is increased soil fertility and an energy source with negative carbon emissions.

Eprida is a company founded by Danny Day, which is attempting to commercialise the idea by building systems that turn farm waste into hydrogen, biofuel, and biochar (see here for a short movie explaining their process).
The Eprida technology uses agricultural waste biomass to produce hydrogen-rich bio-fuels and a new restorative high-carbon fertilizer (ECOSS) ...In tropical or depleted soils ECOSS fertilizer sustainably improves soil fertility, water holding and plant yield far beyond what is possible with nitrogen fertilizers alone. The hydrogen produced from biomass can be used to make ethanol, or a Fischer-Troupsch gas-to-liquids diesel (BTL diesel), as well as the ammonia used to enrich the carbon to make ECOSS fertilizer.

We don't maximize for hydrogen; we don't maximize for biodisel; we don't maximize for char...By being a little bit inefficient in each, we approximate nature and get a completely efficient cycle.

The potential power of biochar lies in this closed loop production process , where agricultural practices involving biochar production see increasing returns of crop yields, energy and soil fertility over time.

Biochar also has potential to address problems such as waste disposal and rural development. A significant proportion of the world's population relies on charcoal as a cooking fuel, the production of which drives deforestation in Africa and other places.

Replacing traditional charcoal kilns with modern pyrolysis units could reduce the demand for wood from forests by increasing the efficiency of energy production and adding the ability to use any source of biomass, including agricultural waste products. This would also help to reduce respiratory diseases in the developing world, particularly amongst children.

There has also been speculation that pyrolysis could be a useful technique for dealing with the huge swathes of Canadian forests that have been killed by pine beetles recently.

Some industry participants believe that energy, rather than agriculture, will be the key driver for adopting biomass pyrolysis. Desmond Radlein of Dynamotive Energy Systems has been quoted as saying "It is wishful thinking that people will switch to renewable fuels unless it is cheaper. All of this is tied to the price of oil; as it goes up, many more things are possible."

Another company active in the pyrolysis sector is Best Energies. Technical Manager Adriana Downey recently had an interview with Beyond Zero Emissions, talking about some of the pilot programs they have been running and plans to build the first fully commercial scale pyrolysis plant in Australia.
Lukas's program with the NSW DPI (Department of Primary Industries) in Northern NSW have basically taken some of the agrichar material that we've made here at Best Energies and they've been trialling that material in different agronomic applications to see how the agrichar, when its applied, can help crop-productivity and improve the sustainability of agriculture as well as, and what you guys are more interested in, sequester carbon long-term in soils and also decrease the potent greenhouse gas nitrous oxide emissions from soil. ...

The agrichar when it's applied to the soil has a good effect on the general physical structure of the soil. Because the agrichar has a really high surface area, it means that there's lots of pores in the soil which can then retain moisture and act as little reservoirs for the water to be retained in the soil. As well as this, all of the surface area helps to bind nutrients in the soil and also provides a microhabitat for micro organisms in the soil which are essential for the natural processes in the soil which allow micro organisms to flourish.

Carbon Capture Potential

There is a large difference between terra preta and ordinary soils - a hectare of meter-deep terra preta can contain 250 tonnes of carbon, as opposed to 100 tonnes in unimproved soils from similar parent material, according to Bruno Glaser, of the University of Bayreuth, Germany. The difference in the carbon between these soils matches all of the carbon contained in the vegetation on top of them.

The ABC's "Catalyst" program last year had a feature on "Agrichar – A solution to global warming ?" (shown below) in the lead up to an international biochar conference in Terrigal, NSW, which included Tim Flannery talking about the potential for sequestering gigatonnes of carbon in the soil.

This year's International Biochar Initiative conference has just been held in Newcastle-upon-Tyne in the UK.

It is not yet clear what the limits are to how much biochar can be added to the soils using these techniques, however some fairly extravagant claims about biochar's capacity to capture carbon have been made. Soil scientist and author of "Amazonian Dark Earths: Origin, Properties, Management" Johannes Lehmann believes that a strategy combining biochar with biofuels could ultimately offset 9.5 billion tons of carbon per year - an amount equal to the total current fossil fuel emissions. Lehmann also notes that unlike biodiesel and corn ethanol, biochar doesn’t take land away from food production.

If true, this would be an interesting form of geoengineering to try and reverse the effects of global warming (and one far less risky than some of the alternatives proposed) but I would still question our ability to turn all the world's oil, coal and gas reserves back into rich soil via burn - atmosphere - pyrolysis loop.


A number of criticisms have been made about biochar. These include:

* The technology to implement the process is still immature.
* Scientists don’t know how much charcoal farmers should use, how they should apply it, or which feedstocks work best.
* Farmers are reluctant to spread unproven products on their fields, so the few companies manufacturing biochar have struggled to find buyers.
* Charcoal production can generate toxic waste if performed incorrectly.
* The energy needed to produce, transport, and bury biochar could outweigh the carbon savings.
* Some analysts say the economics of the process will not be acceptable until carbon markets are established, allowing farmers to earn carbon credits for applying biochar to their fields.
* Some environmental activists claim that applying the process on a large scale would result in further rainforest clearing which would actually degrade soil quality and increase global warming.

Rhizome In The Amazon

Jeff Vail recently had a post on a "Rhizome Template in the Amazon ?", which looked at a paper by Mark Heckenberger suggesting that a dense civilization of networked villages once existed in the Amazon, which Jeff noted was interesting because it "appears to show a form of organization that permits density without significant hierarchy".

The paper shows that the Xingu region of the Amazon was once populated by a grid-like pattern or villages, each connected by a precisely aligned network of roadways (the Xingu river is the Amazon's second longest tributary, with the region currently experiencing tension over plans to dam the river).
Here's an alternate mode of organization--a networked "grid," "lattice," or "peer-to-peer" structure of small, minimally self-sufficient villages, or "rhizome" as proposed in my article The Hamlet Economy. The Xingu settlement structure seems to consicously model itself in the latter pattern. Heckenberger even notes that each village was surrounded by a buffer zone of "managed parkland," exactly the kind of fall-back, resiliency-enhancing production zone that I recommended for rhizome. Here's a link to a satellite image of one section fo Xingu settlement.

Did this Xingu civilization really develop a dense, ecologically sustainable civilization without hierarchal structure? Or did they simply find a new way to impose hierarchy without developing the signatures of "central places"? Was this a conscious reaction to prior abuses of hierarchy, or simply an expedient to survival in the dense forrests and poor agricultural soils of the Amazon? We don't know the answers to these questions at this time, but the research of Heckenberger and his colleagues suggests that there is still a great deal for us to learn from the past about how we can best live in the future

Heckenberger also examined the terra preta pockets in the region, which is described briefly in an interesting article by Charles Mann in The Atlantic Monthly called "1491". Scientific American also notes the correlation between the lost cities of the Amazon and terra preta in "Ancient Amazon Actually Highly Urbanized, as does The Vermont Quarterly in "Pay Dirt".
Terra preta, Woods guesses, covers at least 10 percent of Amazonia, an area the size of France. It has amazing properties, he says. Tropical rain doesn't leach nutrients from terra preta fields; instead the soil, so to speak, fights back. Not far from Painted Rock Cave is a 300-acre area with a two-foot layer of terra preta quarried by locals for potting soil. The bottom third of the layer is never removed, workers there explain, because over time it will re-create the original soil layer in its initial thickness. The reason, scientists suspect, is that terra preta is generated by a special suite of microorganisms that resists depletion. "Apparently," Woods and the Wisconsin geographer Joseph M. McCann argued in a presentation last summer, "at some threshold level ... dark earth attains the capacity to perpetuate—even regenerate itself—thus behaving more like a living 'super'-organism than an inert material."

In as yet unpublished research the archaeologists Eduardo Neves, of the University of São Paulo; Michael Heckenberger, of the University of Florida; and their colleagues examined terra preta in the upper Xingu, a huge southern tributary of the Amazon. Not all Xingu cultures left behind this living earth, they discovered. But the ones that did generated it rapidly—suggesting to Woods that terra preta was created deliberately. In a process reminiscent of dropping microorganism-rich starter into plain dough to create sourdough bread, Amazonian peoples, he believes, inoculated bad soil with a transforming bacterial charge. Not every group of Indians there did this, but quite a few did, and over an extended period of time.

When Woods told me this, I was so amazed that I almost dropped the phone. I ceased to be articulate for a moment and said things like "wow" and "gosh." Woods chuckled at my reaction, probably because he understood what was passing through my mind. Faced with an ecological problem, I was thinking, the Indians fixed it. They were in the process of terraforming the Amazon when Columbus showed up and ruined everything.

Scientists should study the microorganisms in terra preta, Woods told me, to find out how they work. If that could be learned, maybe some version of Amazonian dark earth could be used to improve the vast expanses of bad soil that cripple agriculture in Africa—a final gift from the people who brought us tomatoes, corn, and the immense grasslands of the Great Plains.

All in all I think biochar is worth exploring further in some depth.

Further Reading:

Nature: Putting the carbon back "Black is the new green":

Biochar overview from Cornell University:

Terra Preta web site from the University of Bayreuth

The Earth Science Forum:

Biochar summary from Georgia Tech:

Terra preta mailing list:

FAO: Organic Agriculture And The Environment

WorldChanging: A Carbon-Negative Fuel

Hen and Harvest: Black Magic

Peak Energy: On population growth and the green revolution - "The Fat Man, The Population Bomb And The Green Revolution"

Peak Energy: On worms and soil - "The Turning Of The Worm"

Peak Energy: On Mycelium - "Nature's Internet: The Vast, Intelligent Network Beneath Our Feet"

(Hat tip to Erich J Knight and Aaron Newton for providing some of the links used in the post)